Where is James Webb Telescope and Can We Save Hubble?


The Hubble Space Telescope has been one of the most valuable scientific projects of recent times some even say that we've learned more with Hubble than we did with Apollo but like all good things it must come to an end and that end will be coming in the not to distant future. But the Hubble has a successor waiting in the wings the James Webb Space Telescope this builds on the success of the Hubble but with 21st century technology and promises even greater discoveries, the only problem is that it's now 14 years late and about 10 times over budget and still won't be launched until 2021 so why can't we keep Hubble going and why is the JWST so late and so expensive. Big projects like the James Webb Space Telescope are often beset by delays and problems.The Hubble itself is no stranger to controversy, designed in the 1970s it was due to be launched in 1983 but with technical issues, budget restrictions and the Challenger disaster it was delayed for seven years. Only when it was in orbit did they find that the most perfectly ground mirror in history had been made with a tiny error in its shape effectively making it short-sighted. It took a further three years before a fix was created to finally get it working as it should. The Hubble was designed to be serviced and upgraded in orbit and over the last 25 years it has undergone five service missions this was all done using the Space Shuttle and at the end of each mission the shuttle would move the Hubble to a higher orbit. This is done because although Hubble is in orbit in space the height of this orbit is still low enough to be in the very, very thin upper atmosphere and this creates drag which slows it down over time this slowing down causes the orbit to decay and become lower which increases the drag which slows it down more which makes it come lower which increases the drag and so on and so forth and if nothing is done then eventually it will crash back to earth and burn up. On October 5th 2018 Hubble went into sleep mode when one of its gyroscopes failed. These are devices which are used to help guide and keep its orientation in orbit and although it does have six four have now failed. Three of the six were an older design and it was to be expected but this was one of the newer design ones although it ideally needs three to operate one for each axis the X Y and Z, new operational techniques mean but it can work with just one. As part of the ongoing servicing of Hubble, the newer design gyros along with a list of other equipment had been installed on a previous service mission but these are mechanical devices and they will wear out eventually. The problem is we no longer have a space shuttle to do any further service missions or boost Hubble's orbit so even if nothing else goes wrong Hubble will eventually fall back to earth somewhere between 2028 and 2040. This rather vague date is because it's the sun's activity that affects the expansion of the Earth's atmosphere and ultimately the atmospheric drag on Hubble and that's something which we can only estimate into the future. But it wasn't planned to end like this one of the scenarios was that the Hubble would be brought back to earth by the shuttle and maybe placed somewhere like the Smithsonian Museum. If there is the political will Hubble's life could be extended, there has been talk of a commercial mission using a manned version of a Dream Chaser to service Hubble and boost its orbit just in case there are further delays with the James Webb Space Telescope or god forbid but something happens to it during its launch but either way we now just don't have a vehicle that could bring the Hubble safely back to earth. But why is the James Webb taking so long to quite literally get off the ground. Well one of the reasons is where it will take up its final position. Unlike the Hubble which is just 540 kilometres above the earth the James Webb will actually orbit the Sun 1.5  million kilometres away from Earth at the second La Grange point or L2 where the gravitational effects of a Sun the moon and the earth cancel each other out and allow it to be in a stable orbit with regard to all three.This means that fixing the James Webb unlike the Hubble if something were to go wrong would range from be extremely difficult to the nigh on impossible especially when we don't even have any manned spacecraft capable of traveling out that far. So everything has to work perfectly which means testing, testing and more testing and even testing the tests.The memory of the Hubble Fiasco which was basically down to a failure of testing looms large in the minds of Northrop Grumman the primary contractor and the others involved. The other issue is that no one has built anything quite like the James Webb before. At the time of its conception at least ten of the technologies required had yet to be invented things like the giant five layer Sun shield for size of a tennis court that will take two weeks to deploy from it's folded up form and it's not only the detectors for sun shield and the control systems which will have to work at just a few degrees above absolute zero. Everything on the detection side of a telescope must be as cold as possible so as not to interfere with the tiny amounts of infrared light that the James Webb is looking for from the farthest reaches of the universe from the very first galaxies that formed after the Big Bang. This includes the mirror which are 6 and 1/2 meters across has 6.25 times more light collecting area than Hubble which had a 2.4 meter mirror. A single mirror this large wouldn't fit into any existing spacecraft so it's made up of 18 hexagonal sections which are individually controlled to focus for light onto the sensors. Inventing the technologies, ironing out the bugs and the exhaustive testing of these brand-new ideas takes a lot of time and a lot of money and this is the other main reason why is taking so long to get the Space Telescope ready. Back in 1996 when the JWST was conceived the original price was $1 billion and it was expected to be launched around 2007 but equally no one at the time actually knew how to build it and this was very much a best-guess estimate. It's been said that NASA projects like this are often wildly optimistic and are pitched low so as not to scare off potential funding knowing that we can always go back and ask for more. But as time has gone by the difficulties have began to mount up and so did the costs. This meant that NASA has to keep going back to Congress for more funding which took more time and delayed the whole project. This repeating process has now gone on and on until now the total is expected to be just short of $10 billion. The problem for the government is that if it pulled the plug then not only will science be losing a highly anticipated tool but they will have spent billions with nothing to show for it which in some ways would be worse and is also making the project almost too big to fail from a fiscal point of view. Some commentators have said that it was all done backwards and that we should have built it with existing technologies which have an own price tag. The problem with this argument is that it would have never been built because we didn't have the technology to do so and waiting for someone to invent it without an end goal just isn't going to happen. If this methodology had been applied to Apollo we would have never gotten to the moon.So we may well be stuck with a price tag but the least NASA can do now is try to eliminate as many of the possible points of failure as I can this is likely to become the most highly scrutinized project in space history so far but at least they can console themselves but it looks like an absolute bargain compared to the $400 billion for the development of just one plane the f-35.

So what do you think we should do with the Hubble fix it or leave it to a controlled reentry burn up and what's your thoughts about the JWST let me know in the comments below, Thanks for watching.

Post a Comment